Topological Hall Effect Induced by Chiral Spin Textures at the Ferroelectric/Ferromagnetic Interface

Chiral spin textures, largely driven by the Dzyaloshinskii-Moriya interaction, offer significant potential for next-generation computing technologies due to their chirality and topological stability. Ferroelectric/ferromagnetic van der Waals heterostructures are particularly appealing because they can combine interfacial inversion-symmetry breaking and spin-orbit coupling to promote interfacial Dzyaloshinskii-Moriya interaction, while switchable ferroelectric polarization provides a nonvolatile tuning knob. This study investigates interfacial chiral spin textures in few-layer ${\mathrm{Fe}}_3{\mathrm{GeTe}}_2$ / $\alpha$ - ${\mathrm{In}}_2{\mathrm{Se}}_3$ heterostructures. Two groups of topological Hall signals are identified just below and above the coercive field, and thickness-dependent transport reveals a notable reduction in critical temperature with increasing ${\mathrm{Fe}}_3{\mathrm{GeTe}}_2$ layer thickness. Low-temperature magnetic force microscopy images reveal two types of magnetic bubbles with opposite magnetic contrasts near the coercive field, each associated with distinct topological Hall signals. Together with atomistic spin-dynamics simulations and first-principles calculations, these results support the formation of interfacial DMI-stabilized chiral spin textures. Switching the ferroelectric polarization of the $\alpha$ - ${\mathrm{In}}_2{\mathrm{Se}}_3$ layer further enables nonvolatile modulation of both anomalous and topological Hall effects. The resulting ferroelectric and magnetic bistabilities generate four distinguishable Hall resistance states programmable by electric and magnetic fields. These findings highlight the potential of van der Waals interfaces for advanced device applications.